Asthma administration routes

Pulmonary delivery of drugs is the administration route of choice in respiratory diseases such as chronic obstructive pulmonary disease and asthma. Different devices are available, including metered-dose inhalers, dry powder inhalers, and nebulizers, and nearly 80% of asthmatic patients worldwide use metered dose inhalers (1). Chlorofluorocarbons have been used as an aerosol propellant in metered-dose inhalers however, they deplete the ozone layer and are being replaced by more environment-friendly propellants, even though the contribution of aerosols of this type to the total global burden of chlorofluorocarbons is less than 0.5%. The first chloro-fluorocarbon-free metered-dose inhaler for asthma treatment was approved by the FDA in 1996 (2) and the European Union has set 2005 as a target date for the withdrawal of all chlorofluorocarbon-based inhalers (1). In the USA, prescriptions for chlorofluorocarbon-free medications rose from 16.4 million in 1996 to 33.8 million in 2000 (2). Most of the chlorofluorocarbon-free medications were steroids for nasal use (27.2 million). However, chlorofluorocarbon-containing medications stiU represented two-thirds of all prescriptions and increased from 63.0 to 67.6 million dispensed (2). 

Direct airway administration of asthma medications through inhalation is the most efficient route and minimizes systemic adverse effects. 

There is no evidence that intravenous corticosteroid administration is more effective than oral administration, and the oral route is preferred in acute severe asthma.3 There are also few data to guide selection of initial corticosteroid doses. Recommended doses for acute severe asthma are shown in Table 11-5, page 227 however, recent data indicate that... 

Flunisolide is a fast-acting corticoid designed for the treatment of allergic rhinitis, asthma, and other allied respiratory disorders in humans. As the quantum of drug delivered by inhalation (/. e., the usual route of administration of the drug), is invariably small, the plasma-levels attained can also be fairly small. Hence, there is a dire need for a sensitive method of plasma concentration evaluation which is satisfied by radioimmunoassay. 

Budesonide respules - Administer by the inhaled route via jet nebulizer connected to an air compressor in asthmatic patients 12 months to 8 years of age. Improvement in asthma control following inhaled administration of budesonide can occur within 2 to 8 days of initiation of treatment, although maximum benefit may not be achieved for 4 to 6 weeks. It is desirable to downward-titrate to the lowest effective dose once asthma stability is achieved. In symptomatic children not responding to nonsteroidal therapy and in patients who require maintenance therapy of their asthma, a starting dose of 0.25 mg once daily may also be considered. 

Dosage forms that use the inhalation route are often preferred in asthma and other obstructive pulmonary diseases. Systemic administration by the oral route or by injection is typically reserved for acute or severe bron-choconstrictive disease [see text for details]. 

Aminophylline is used in the treatment of asthma (as a bronchodilator) and in chronic obstructive pulmonary disease. In acute bronchospasm, aminophylline should not be given by the intravenous route the oral route is preferred. Parenteral administration can cause pain and is not recommended. Aminophylline is used as a cosmetic to remove fat from the thigh.45... 

Inhalation Inhalation provides the rapid delivery of a drug across the large surface area of the mucous membranes of the respiratory tract and pulmonary epithelium, producing an effect almost as rapidly as by intravenous injection. This route of administration is used for drugs that are gases (for example, some anesthetics), or those that can be dispersed in an aerosol. The route is particularly effective and convenient for patients with respiratory complaints (for example, asthma or chronic obstructive pulmonary disease) as drug is delivered directly to the site of action and systemic side effects are minimized (see p. 219). 

For any minor injuries sustained during athletic training NSAIDs and corticosteroids (topical, intra-articular) suppress symptoms and allow the training to proceed maximally. Their use is allowed subject to restrictions about route of administration, but strong opioids are disallowed. Similarly, the IOC Medical Code defines acceptable and unacceptable treatments for relief of cough, hay fever, diarrhoea, vomiting, pain and asthma. Doctors should remember that they may get their athlete patients into trouble with sports authorities by inadvertent prescribing of banned substances. ... 

The relatively high selectivity of inhaled bec-lomethasone in asthma is due to a combination of route of administration, high potency and rapid conversion to inactive metabolites by the liver of any drug that is absorbed (see asthma, skin) but yet hypothalamic/pituitary suppression and systemic toxicity occasionally occur. 

Intracoronary adenosine has been compared with intravenous adenosine for the measure of fractional flow reserve in 52 patients with coronary artery lesions (44). The intravenous dose was 140 micrograms/kg/minute and the intracoronary bolus dose was 15-20 micrograms to the right coronary artery and 18-24 micrograms to the left coronary artery. The two routes of administration were equally effective in measuring hyperemic flow, and adverse effects were limited to two patients who received intravenous adenosine one patient had severe nausea and one patient with asthma had an episode of bronchospasm. 

However, this route of administration is eminently logical, in several circumstances. For the acute treatment of migraine, oral drugs are often vomited (sumatriptan). For treating acute asthma, children often cannot use an inhalational device properly (theophyliine). For perioperative antibiotics, patients are often nil by mouth (metronidazole). For inflammatory bowel disease and proctitis, this is simply a topical administration. 

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